I don’t think this “conversation” is over at all. If we had to
declare a conclusion today, I wouldn’t bet on mobile ads being the
clear “winner” over in-app purchase. And it would be a miserable
outcome for all three interested parties — users, developers, and
advertisers — if ads do end up being the de facto way for apps to
make money.

I also think it’s a bit silly to simply look at all apps. Sturgeon’s Law certainly applies to apps — most are crap. (If anything, 90 percent is way too low a number to describe how many are crap.) What’s the split on ad-backed vs. paid for non-crap apps?